Hartony, Harold E., ed. Aircraft Spotters' Guide. New York: National Aeronautics Council, Inc., 1942

Hartony, Harold E., ed. Aircraft Spotters' Guide. New York: National Aeronautics Council, Inc., 1942, Volume: Gilbert C589. Robert L. Gilbert First Issues collection, Gilbert. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/526152 Accessed December 28, 2025.